Thymoquinone vapor significantly affects the results of Staphylococcus aureus sensitivity tests using the standard broth microdilution method

The broth microdilution (BMD) method is widely used for the determination of minimum inhibitory concentrations of antimicrobial agents, including volatile oils and their components. In this series of various experiments, we have demonstrated the influence of thymoquinone (TQ) vapor on the results of the BMD test performed with Staphylococcus aureus as a model organism. The spread of vapor from the TQ containing wells (32–512 μg/mL) caused the complete inhibition of staphylococcal growth in adjoining wells initially containing bacterium-inoculated pure Mueller–Hinton broth only and thus produced false positive results of the test. The ability of TQ to pass into the adjoined wells was subsequently confirmed by gas chromatography–mass spectrometry, whereas TQ at concentrations up to 84 μg/mL was detected in these wells after five hours. Based on these results, we suppose that vapors of TQ as well as of other naturally occurring volatile compounds and their mixtures (for example essential oils and plant extracts) can significantly influence results of the standard BMD assay. These observations, therefore, call for development of new appropriate BMD method suitable for assessment of antimicrobial activity of volatile substances.     

Synthesis and antimicrobial evaluation of pogostone and its analogues

Pogostone (PO) is one of the secondary metabolites from Pogostemon cablin (Blanco) Benth. (Lamiaceae), serving as the effective component of the antimicrobial activity. In this study, PO and a series of its analogues were synthesized by the reaction of dehydroacetate and aldehydes in tetrahydrofuran under a nitrogen atmosphere. Their activities against Candida albicans, Gram positive bacteria and Gram negative bacteria were evaluated. The antifungal results demonstrated that PO (MIC ranged from 12 to 97 μg/mL against all strains, MFC ranged from 49 to 97 μg/mL against all strains) and A3 (MIC ranged from 12 to 49, MFC over 195 μg/mL) showed a strong activity against Candida albicans. While A1 (MIC ranged from 49 to 97 μg/mL) and A2 (MIC ranged from 24 to 49 μg/mL) have only shown effect against Guangzhou clinical isolates, the antibacterial results demonstrated that PO and its analogues showed no effects against the tested bacteria strains. This study suggests that pogostone analogues, with the appropriated structure modification, represented a kind of promising antifungal agents.     

Life cycle inventories of roundwood production in northern Wisconsin: Inputs into an industrial forest carbon budget

Carbon budgets are developed to understand ecosystem dynamics and are increasingly being used to develop global change policy. Traditionally, forest carbon budgets have focused on the biological carbon cycle; however, it is important to include the industrial forest carbon cycle as well. The overall objective of this study was to quantify the major carbon fluxes associated with the production of Wisconsin's industrial roundwood, by using life cycle inventory (LCI) methodology to produce an industrial forest carbon budget. To achieve this objective we (1) developed carbon LCIs for the harvest process for three major forest ownerships (state, national, and private non-industrial), (2) developed carbon LCIs for a dimensional lumber and two oriented strand board (OSB) mills and (3) completed a scaled version of 1 and 2 to include more Wisconsin forestlands and to incorporate the other major processes within the industrial forest carbon cycle (e.g. primary mill, secondary mill, product use and product disposal processes of the industrial forest carbon cycle). The carbon budgets for the harvesting process of the Chequamegon-Nicolet National Forest (CNNF), the Northern Highland American Legion State Forest (NHAL), and the non-industrial private forests that participated in the managed forest laws of Wisconsin (MFL-NIPF) were 0.10, 0.18 and 0.11 tonnes C ha⁻¹ year⁻¹), respectively. The dimensional lumber and OSB products were both net carbon sources, and released 0.05–0.09 tonnes C/tonnes C processed). More carbon is sequestered than released within the industrial forest carbon cycle of Wisconsin's national (6 g C m⁻² year⁻¹), state (12 g C m⁻² year⁻¹) and non-industrial private forests (7 g C m⁻² year⁻¹). Using published net ecosystem production data we estimate that the net forest carbon cycle budget (sum of the biological and industrial C cycle, [Gower, S.T., 2003. Patterns and mechanisms of the forest carbon cycle. Ann. Rev. Environ. Resour. 28, 169–204]) for the CNNF ranges between −897 and 348 g C m⁻² year⁻¹. Life cycle inventories of wood and paper products should be clear and explicitly state what processes are included, so that results can be used by policy makers and future researchers.     

Hormone-sensitive lipase is involved in the action of hydroxysafflor yellow A (HYSA) inhibiting adipogenesis of 3T3-L1cells

BackgroundSafflor yellow A (SY) has been demonstrated to be beneficial to cardiovascular system. Our previous study showed that hydroxysafflor yellow A (HSYA), a main component of SY, could increase peroxisome proliferator-activated receptor γ mRNA expression. In this study, we investigate the effect of HSYA on the proliferation and adipogenesis of mouse 3T3-L1 preadipocytes.MethodsThe proliferation and adipogenesis of 3T3-L1 cells treated with HSYA was studied by 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide (MTT) spectrophotometry, Oil Red O staining and intracellular triglyceride assay methods. HSL mRNA expression and promoter activity were studied by real-time quantitative RT-PCR, transient transfection and dual luciferase reporter gene methods.ResultsHSYA (0.1 mg/L) significantly inhibited the proliferation of 3T3-L1 cells when compared with control cells in 8 h. This effect was further enhanced with the extension time (24 to 96 h) and an increase of concentration of HSYA (1–10 mg/L). The maximal inhibitory action was observed at 0.1 mg/L HSYA in 72 h (86 ± 11.8% vs. 100 ± 4.1%, p < 0.01). HSYA notably reduced the amount of intracellular lipid and triglyceride content in adipocytes to 85% (1 mg/L) and 75% (100 mg/L) on Day 4 following the differentiation, respectively, while increased HSL mRNA expression and promoter activities to 2.7 fold and 1.55 fold, respectively (p < 0.01), in differentiated 3T3-L1 adipocytes.ConclusionsHSYA inhibits the proliferation and adipogenesis of 3T3-L1 preadipocytes. The inhibitory action of HYSA on adipogenesis may be due to the promotion of lipolytic-specific enzyme HSL expression by increasing HSL promoter activity.     

The antibiofilm activity of lingonberry flavonoids against oral pathogens is a case connected to residual complexity

The antimicrobial activity of lingonberry (Vaccinium vitis-idaea L.) was evaluated against two oral pathogens, Streptococcus mutans and Fusobacterium nucleatum. Long-bed gel permeation chromatography (GPC; Sephadex LH-20) yielded purified flavonoids, with the most efficient minimum inhibitory concentrations (MICs) against planktonic cells in the anthocyanin and procyanidin primary fractions against F. nucleatum (63–125 μg/ml) and in the procyanidin rich fraction against S. mutans (16–31 μg/ml). The purified flavonol glycosides and procyanidins inhibited biofilm formation of S. mutans (MICs 16–31 μg/ml), while the corresponding reference compounds showed no activity. Secondary GPC purification yielded flavonol glycosides devoid of antibiofilm activity in the 50% MeOH fraction, while elution with 70% acetone recovered a brownish material with activity against S. mutans biofilm (MIC 8 μg/ml). Even after HPLC-PDA, NMR, and MALDI-TOF analyses, the structural identity of this material remained unknown, while its color and analytical characteristics appear to be consistent with flavonoid oxidation products.     

Nutrient uptake and growth of young trees in a P-deficient soil: Tree species and phosphorus effects

Phosphorus deficiency is widespread in the subhumid highlands of eastern Africa but there are few data on the effect of P deficiency on the growth of agroforestry tree species. We studied the effect of P application on growth, nutrient uptake and dry matter partitioning in young trees of Calliandra calothyrsus, Cedrela serrulata, Eucalyptus grandis, Grevillea robusta, Markhamia lutea, Senna spectabilis, and Sesbania sesban on a P-deficient soil (Kandiudalfic Eutrudox, bicarbonate-EDTA extractable P = 1 mg kg⁻¹) in western Kenya. The trees were grown at two P levels (control and 500 kg added P ha⁻¹) at 1 m² spacing in a randomized complete block design with three replications. Leaf K concentrations were in the low range for all species (5–9 mg g⁻¹) and K deficiency may have limited responses to P. Averaged over species, P addition increased aboveground shoot dry matter by a factor of 2.6 at 62 and 124 days, but the response decreased to 1.3 at 325 days. The increases at 62 days were large in sesbania (5.4) and eucalyptus (3.2) but small in calliandra (1.4) and markhamia (1.1). Relative response to P was more strongly correlated with shoot growth rate per unit root length among species than with shoot growth rate alone. Calliandra, which had high early growth rate but low response to added P, had an exceptionally high root length (6.0 km m⁻²) compared with the other species (0.3–2.1 km m⁻²). P addition increased N and P content but decreased final shoot K content in sesbania and calliandra, and had little effect on K content in the other species. The high-yielding species (eucalyptus, sesbania and calliandra) accumulated more than 30 g N and 2 g P m⁻² in shoots in 325 days of growth. The proportion of total shoot N in wood (branch + stem) was in a higher range (67–75%) in the shrubby species (sesbania, calliandra, senna) than in the upperstorey tree species (38–43%). Slow early shoot growth relative to total root length, and high specific root length (root length per unit root mass) are proposed as criteria for the selection of species and provenances that are well adapted to P deficient soils.     

Deforestation and reforestation needs in Mongolia

This paper provides a brief background to Mongolia’s forest condition in 1994. Over recent years, since the introduction of a market economy and decentralization, there has been a rapid change in the forest sector. In 1994, the total designated forest area of Mongolia was 17.5 million ha, including 12.7 million ha of closed forest or 8.1% of the total land area. The forests are subdivided into (i) special forests; (ii) protection forests; (iii) industrial forests, based on their basic functions. The main causes of deforestation in Mongolia are (i) increasing livestock numbers; (ii) increasing demand for fuel and industrial wood; (iii) the impact of forest fires. Grazing and browsing in forest areas are most destructive to plantations and tree growth, causing deformities and stunting growth. Livestock breeding without adequate management system has major negative impacts on remnant forest growth. According to some statistics, the forest area has decreased by 1.2 million ha over the last 20 years. At present, production and supply of sawn timber boards for the domestic market is carried out without any regard to the actual quantity required. Major wood-based products in Mongolia are railway sleepers, windows and doors, wooden boxes for packing and school and office furniture. Products are also made for the frames of the traditional Mongolian “Ger” and specialized furniture for the interior. By 1996, Mongolia’s forest industry had total sales of US$ 2.1 million, which was 13% more than the previous year.Between 1992 and 1995, the incidence of fires in forest areas increased because a sharp rise in the number of people using the forest and steppe areas to cut trees, pick berries and nuts, collect firewood and deer horns, and to hunt. Mismanagement and negligence of the relevant authorities also contributed to this situation. It is necessary to take strong measures in order to identify the social and economic causes of fire outbreaks. Since 1970, forestry and timber harvesting companies have begun to harvest wild seeds, breed seedlings and conduct reforestation activities. Between 1980 and 1990, on nationwide level, over 20 million standard seedlings were planted in over 40 permanent nurseries to supply the reforestation work. At that time the scope of reforestation expanded. The total area planted over some 30 years has been very small compared to the deforestation. Even if just the area harvested during that period is considered, the reforestation rate is still lower than 15%.     

The cytotoxic activities of cardiac glycosides from Streptocaulon juventas and the structure–activity relationships

A series of cardiac glycosides were isolated and identified from the anti-tumor fraction of the root of Streptocaulon juventas in previous studies. In the present research, the cytotoxic activities of the 43 cardiac glycosides on three cell lines, human lung A549 adenocarcinoma cell, large cell lung cancer NCI-H460 cell and normal human fetal lung fibroblast MRC-5 cell, were evaluated in vitro. Most of the tested compounds showed potent inhibitory activities toward the three cell lines. Then, the structure–activity relationships were discussed in detail. It was indicated that hydroxyl and acetyl groups at C-16 increased the activity, whereas hydroxyl group at C-1 and C-5 can both increase and decrease the activity. Two glucosyl groups which were connected by C1′ → C6′ showed better inhibitory activity against cancer cell lines, while the C1′ → C4′ connection showed stronger inhibitory activity against the normal cell line. Also, this is the first report that the activities of these compounds exhibited different variation trends between A549 and NCI-H460 cell lines, which indicated that these compounds could selectively inhibit the cell growth. The results would lay a foundation for further research on new anti-tumor drug development.     

Can intensive management accelerate the restoration of Brazil's Atlantic forests?

Only 7% of the once extensive forest along the eastern coast of Brazil remains, and much of that is degraded and threatened by agricultural expansion and urbanization. We wondered if methods similar to those developed to establish fast-growing Eucalyptus plantations might also work to enhance survival and growth of rainforest species on degraded pastures composed of highly competitive C₄ grasses. An 8-factor experiment was laid out to contrast the value of different intensities of cultivation, application of fertilizer and weed control on the growth and survival of a mixture of 20 rainforest species planted at two densities: 3 m × 1 m, and 3 m × 2 m. Intensive management increased seedling survival from 90% to 98%, stemwood production and leaf area index (LAI) by ～4-fold, and stemwood production per unit of light absorbed by 30%. Annual growth in stem biomass was closely related to LAI alone (r² = 0.93, p < 0.0001), and the regression improved further in combination with canopy nitrogen content (r² = 0.99, p < 0.0001). Intensive management resulted in a nearly closed forest canopy in less than 4 years, and offers a practical means to establish functional forests on abandoned agricultural land.     

Genotypic variation in wood density and growth traits of poplar hybrids at four clonal trials

Wood density is considered as one of the most important wood properties which affects the properties and value of both fibrous and solid wood products. The present study was intended for evaluating the possibilities of improving wood quality and growth of poplar hybrids. Wood density components of individual growth rings (minimum and maximum wood density, average ring density) and growth traits (tree height, dbh, stem volume) were measured in four 10- and 12-year-old clonal trials of four poplar hybrids, Populus deltoides × P. nigra, P. trichocarpa × P. deltoides, P. maximowiczii × P. balsamifera, and P. balsamifera × P. nigra, as well as P. deltoides. Wood density components of individual growth rings were obtained from microdensitometeric profiles measured with a direct reading X-ray densitometer. Site had a moderately significant effect on wood density and a highly significant effect on tree growth. The hybrid effect was highly significant (P < 0.001) for most traits. Minimum, maximum and weighted wood densities were found to be under strong genetic control, with clonal repeatabilities varying between 0.45 and 0.81. The coefficient of genotypic variation (CV_G) for wood density at individual sites ranged from 4.0 to 6.8%, whereas CV_G for dry fiber weight (mass) reached 32.8% with repeatabilities of up to 0.67. A small but significant (P = 0.028) hybrid × environment interaction was found for dry fiber weight. The highest ecological sensitivity was found for P. deltoides × P. nigra, with ecovalence reaching 32.3%. Clonal × environment interaction was significant for weighted, average, and minimum wood density. Significant negative genotypic correlations between stem volume and wood density ranged from −0.39 to −0.74. One possible strategy in tree breeding would be to maximize wood fiber production through selection for dry fiber weight.     

Diameter increment patterns among 106 tree species in a logged and silviculturally treated Costa Rican rain forest

Studies of growth rates of trees in managed neotropical forests have rarely employed complete botanical identification of all species, while published information for Central American lowland rain forests largely concerns forests free of recent disturbance. We studied diameter increments of trees in a managed Costa Rican rain forest. The Pentaclethra macroloba-dominated forest was located on low hills with Ultisols in Holdridge's Tropical Wet Forest life zone. The 540 m × 540 m (29.2 ha) experimental area was lightly logged during 1989–1990. The 180 m × 180 m (3.24 ha) experimental plots comprised a 100 m × 100 m (1.0 ha) central permanent sample plot (PSP) with a 40-m wide buffer strip. Post-harvest silvicultural treatments were liberation/refinement (in 1991) and shelterwood (in 1992), applied under a complete randomized block design with three replicates, using logged but untreated plots as controls. All live trees ≥10 cm DBH in the PSPs, were identified to species; data reported are for 1993–1996. Cluster analysis was used to group species on the basis of the median and quartiles of their diameter increment distributions, separating data by silvicultural treatments; five diameter increment groups were established and subdivided on the basis of the adult height of each species (four categories), giving 17 species groups in the final classification. Adult height and silvicultural treatment made a significant contribution to growth rate variation. Median annual increments of the slowest-growing species groups, which featured many under- and middle story species, were ca. 1 mm; those for the fastest growing species, which were mainly canopy and emergents, were ca. 16 mm. All species in the groups of very fast growth were pioneers, whether short or long-lived, though many other pioneer species did not show fast growth. The proportions of species found in groups of moderate, fast or very fast growth were greater in the silviculturally treated plots than in the controls, and one complete diameter increment group, of fast growth, was only represented in the treated plots. Crown form, crown illumination and presence of lianas in the crown, showed significant correlations with diameter increments, though the importance of these latter two variables varied with silvicultural treatment. The very fast growth groups differed from the others in having higher proportions of trees with well-formed, well-illuminated crowns and an irregular diameter distribution with relatively few individuals in the smallest DBH class. Comparison with data from other neotropical forest sites shows that long-lived pioneers such as Vochysia ferruginea and Jacaranda copaia grow fast or very fast at all sites, while non-commercial canopy and emergent species of Chrysobalanaceae and Sapotaceae appear to be uniformly slow-growing. Growth data for the majority of species are, however, published for the first time.     

Inactivation of jack bean urease by scutellarin: Elucidation of inhibitory efficacy,kinetics and mechanism

In the present study, the inactivation effect of scutellarin (SL) on jack bean urease was investigated to elucidate the inhibitory potency, kinetics and mechanism of inhibition. It was revealed that SL acted as a concentration- and time-dependent inactivator of urease characteristic of slow-binding inhibition with an IC₅₀ of 1.35 ± 0.15 mM. The rapid formation of the initial SL–urease complex with an inhibition constant of K_i = 5.37 × 10^− 2 mM was followed by a slow isomerization into the final complex with the overall inhibition constant of K_i* = 3.49 × 10^− 3 mM. High effectiveness of thiol protectors, such as L-cysteine (L-cys), 2-mercaptoethanol (2-ME) and dithiothreitol (DTT) significantly slowed down the rate of inactivation, indicating the strategic role of the active site sulfhydryl group in the blocking process. While the insignificant protection by boric acid and fluoride from the inactivation further confirmed that the active site cysteine should be obligatory for urease inhibition, which was also rationalized by the molecular docking study. The inhibition of SL on urease proved to be reversible since SL-blocked urease could be reactivated by DTT application and multidilution. The results obtained indicated that urease inactivation resulted from the reaction between SL and the sulfhydryl group.     

Comparison of in vitro antiviral activity of tea polyphenols against influenza A and B viruses and structure–activity relationship analysis

Influenza poses a particular risk of severe outcomes in the elderly, the very young and those with underlying diseases. Tea polyphenols are the natural phenolic compounds in teas, and principally consist of catechins, proanthocyanidins, flavonols, and theaflavins, which antiviral activities have been reported recently. This study is to gain a further insight into potential of various tea polyphenols for inhibiting influenza virus infection. Five tea polyphenols exhibited inhibitory activity against influenza A virus in the trend of theaflavin > procyanidin B-2 > procyanidin B-2 digallate > (−)-epigallocatechin(EGC) > (−)-epigallocatechingallate(EGCG) with IC₅₀ values in the range of 16.2–56.5 μg/ml. Six of the tested compounds showed anti-influenza B virus activity in the order of kaempferol > EGCG > procyanidin B-2 > (−)-EGC ~ methylated EGC > theaflavin with IC₅₀ values in the range of 9.0–49.7 μg/ml. Based on these results, the structure–activity relationship (SAR) was explained as follows. First, the dimeric molecules, such as theaflavin and procyanidin B-2, generally displayed more potent antiviral activity against both influenza A and B viruses than the catechin monomers. Second, the kaempferol for inhibition of influenza B virus indicated that the more planar flavonol structure with only one C-4′ phenolic hydroxyl group in the B ring is necessary for the anti-influenza B virus activity. A similar SAR can be drawn from the assays of another enveloped RNA virus, such as respiratory syncytial virus. These results are expected to provide guides for rational design of antiviral drugs based on polyphenols.     

Growth and carbon stocks of a spruce forest chronosequence in central Europe

Human induced changes in global environmental conditions are expected to influence or, as it is hypothesised in this study, have already influenced the biomass and growth of forest ecosystems. In this study, we reconstruct the history of tree growth and quantify the standing biomass along a chronosequence of six Norway spruce stands (Picea abies [L.] Karst; 16–142 years old) on acid soils in a mountainous region with high nitrogen deposition. The inventories of the study sites, as well as the historical stem growth of the sample trees were compared with common yield tables, representing growing conditions before 1960, to find out if and when significant changes in growth of trees had occurred. The growth at tree level (0.003–0.030 m³ yr⁻¹) was about 150–350% higher than predicted by the yield tables, independent of tree age. Because of low stand densities due to early thinning, the increase of stem growth at stand level (90% higher than yield table predictions) and the stand volume (35% higher than yield table predictions) were not as high as the increase of growth at tree level. Total biomass at stand level (including stems, branches, twigs, needles and roots) ranged between 35 and 180 t C ha⁻¹. Net primary productivity varied between 6 and 13 t C ha⁻¹ yr⁻¹. Intensive tree thinning activities probably stimulated growth of remaining trees, but the observed growth rates were beyond what would be expected from these activities exclusively. Thus it is assumed that the fertilisation effects of increased nitrogen deposition and CO₂ concentration, and improved climatic conditions due to ongoing climate change, have contributed to the observed changes in stem growth and that the thinning activities were synergetic with changing environmental conditions. The implications for carbon sinks as accountable under the Kyoto Protocol are probably small, because changes in environmental conditions are not accountable under the Kyoto Protocol and most of the observed changes in growth took place before 1990, the baseline for the Kyoto Protocol. Additionally, it is assumed that impacts on the carbon balance of forest stands due to changes in the thinning regime after 1990, which would be accountable according to article 3.4 of the Kyoto Protocol, are very small without any synergetic changes in environmental conditions.     

An improved tool for the fabrication of dendrometer bands to estimate growth as function of treatments in slow growing native Prosopis stands

Silvicultural research on slow growing hardwoods, especially hardwoods in semi-arid ecosystems is complicated by the slow growth rates that require long time periods to measure treatment responses. Difficulty in measuring small growth increments with traditional methods results in large measurement errors requiring many replications over long time spans. Permanently mounted dendrometers with a vernier scale can detect diameter changes of 0.25 mm (0.01 in.) and are useful tool for these applications. A tool described by Liming [Liming, F.G., 1957. Homemade dendrometers, J. For. 55, 555–577.] can be used to construct inexpensive, precise dendrometers. Unfortunately this tool is difficult to fabricate due to the very thin slots 0.254 mm (0.01 in.). Additionally, the stylus for this dendrometer is very narrow (<0.25 mm) and not very robust. We report a design for a dendrometer whose slots are five times as wide that is easier to fabricate. The stylus for the new dendrometer is machined on a lathe and is five times thicker and more robust. This paper reports the use of this dendrometer that can measure increase or decrease of 0.25 mm (0.01 in.) in diameter. When used in conjunction with sampling and regression equation development, this system measured significant treatment differences in growth for total biomass and volume in stands that only grew from 1.2 to 2.7 mm in basal diameter per year.     

Characteristics of nobiletin-induced effects on jejunal contractility

Nobiletin, a citrus polymethoxylated flavone, exhibits multiple biological properties including anti-inflammatory, anti-carcinogenic, and anti-insulin resistance effects. The present study found that nobiletin exerted significant stimulatory effects on the contractility of isolated rat jejunal segments in all 6 different low contractile states, and meanwhile significant inhibitory effects in all 6 different high contractile states, showing characteristics of bidirectional regulation (BR). Nobiletin-exerted BR on jejunal contractility was abolished in the presence of c-kit receptor tyrosine kinase inhibitor imatinib or Ca^2 + channel blocker verapamil. In the presence of neuroxin tetrodotoxin, nobiletin only exerted stimulatory effects on jejunal contractility in both low and high contractile states. Hemicholinium-3 and atropine partially blocked nobiletin-exerted stimulatory effects on jejunal contractility in low-Ca^2 +-induced low contractile state. Phentolamine or propranolol or l-NG-nitro-arginine significantly blocked nobiletin-exerted inhibitory effects on jejunal contractility in high-Ca^2 +-induced high contractile state respectively. The effects of nobiletin on myosin light chain kinase (MLCK) mRNA expression, MLCK protein content, and myosin light chain phosphorylation extent were also bidirectional. In summary, nobiletin-exerted BR depends on the contractile states of rat jejunal segments. Nobiletin-exerted BR requires the enteric nervous system, interstitial cell of Cajal, Ca^2 +, and myosin phosphorylation-related mechanisms.     

Pharmacokinetic study of eight coumarins of Radix Angelicae Dahuricae in rats by gas chromatography–mass spectrometry

A sensitive, specific gas chromatography–mass spectrometry (GC–MS) method was established for the quantitative determination of eight coumarins of Radix Angelicae Dahuricae including coumarin, isopsoralen, psoralen, xanthotoxin, bergapten, osthole, imperatorin and oxypeucedanin in rat plasma. Nitrendipine was used as the internal standard (IS). The plasma samples were extracted by acetonitrile. GC separation was accomplished on a DB-5MS column with temperature programmed from 160 °C (17 min) to 190 °C (10 min) at the rate of 20 °C/min, then to 240 °C (5 min) at 20 °C/min, and finally to 280 °C (14 min) at 20 °C/min. The detection was performed on a quadrupole mass spectrometer detector operated by full-scan mode (m/z 50–500). The lower limit of quantitation was 5–10 ng/mL for eight coumarins, and the linear range was 5–1000 ng/mL for the coumarins (R² > 0.9990). All the validation data were within the required limits. After oral administration, the plasma concentration–time curves showed that the time for maximum concentration (T_max) was 1.29 for coumarin, 1.83 for isopsoralen, 1.93 for psoralen, 1.30 for xanthotoxin, 2.04 for bergapten, 0.64 for osthole, 1.41 for imperatorin and 0.51 h for oxypeucedanin. The plasma concentration of the eight coumarins was low, with a mean maximum plasma concentration (C_max) < 6.41 μg/mL. Pharmacokinetic data analysis showed that the eight coumarins had different pharmacokinetic characteristics after oral administration. The method was successfully applied to pharmacokinetic studies of eight coumarins after oral administration in rats.     

α-Glucosidase inhibitory triterpenoids from the stem barks of Uncaria laevigata

A phytochemical study on the ethanolic extract of the stem barks of Uncaria laevigata leads to the isolation and characterization of 18 triterpenoid compounds. Ten of these are new, including one novel heptanortriterpenoid (1), four ursane triterpenes (2–4, 10), and five oleanane triterpenes (5–9). Their structures were established by spectroscopic methods, especially by 2D-NMR and MS analyses. All these isolates were evaluated for their inhibitory effects on α-glucosidase: ursolic acid and 3 showed potent activities with IC₅₀ values of 16 ± 2.2 and 49 ± 3.7 μM, respectively.     

Carapanolides C–I from the seeds of andiroba (Carapa guianensis,Meliaceae)

Five new mexicanolide-type limonoids, carapanolides C–G (1–5), together with two new phragmalin-type limonoids, carapanolides H–I (6, 7), were isolated from the oil of Carapa guianasis AUBLET (Meliaceae) seeds. Their structures were elucidated on the basis of spectroscopic analyses using 1D and 2D NMR spectra and FABMS. Carapanolides C (1), E (3), and I (7) exhibited moderate activity in the P388 (IC₅₀ 17.9 μM in 1, 15.8 μM in 3) and L1210 cell lines (IC₅₀ 13.3 μM in 1, 18.1 μM in 3, 16.9 μM in 7). On the other hand, Carapanolide D (2) exhibited a strong inhibitory effect in the HL-60 cell line (IC₅₀ 11.0 μM), Carapanolides F (4) showed inhibitory activity in the L1210 cell line (IC₅₀ 15.9 μM), and the cytotoxic activity of Carapanolides I (7) was moderate in all cell lines.     

The inhibition of resveratrol to human skin squamous cell carcinoma A431 xenografts in nude mice

Squamous cell carcinoma (SCC) is one of the commonest dermatological malignancies. Resveratrol (Res) is one type of polyphenolic compound which was first identified from the roots of Veratrum grandinorum in 1940. The previous studies found that Res can promote apoptosis of a variety of tumor cell, especially SCC cells. However it is rare to study the inhibition mechanism of Res in the animal model. In this study, through the establishment of human cutaneous SCC A431 xenografts in nude mice, we observed Res inhibition effect and investigated the inhibition mechanism by checking the expression of apoptosis-related factors, p53, ERK and survivin. The results showed that the xenograft volume and weight of Res groups were less than those of the control groups (P < 0.05), but the net body mass of nude mice of Res groups was not significantly different from the control groups (P > 0.05). The apoptotic index of Res groups were significantly higher than the control groups (P < 0.05). The protein and mRNA expression of p53 and ERK were statistically positively correlated (P < 0.05) and significantly increased in Res high- and medium-dose groups compared with the control groups (P < 0.05). Moreover, the protein and mRNA expression of SVV were negatively correlated with p53 (P < 0.05) and lower than the control groups (P < 0.05). The results demonstrate Res inhibitory effect and indicate that the inhibition mechanism of Res is to upgrade the protein and mRNA expression of p53 and to downgrade the protein and mRNA expression of SVV, thus inducing the apoptosis of tumor cells.